Warrants (Schedule Of Assumptions Used In Calculating Fair Value Of Warrants) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Trading market prices	$ 0.93	$ 2.02
Estimated future volatility	105.00%	104.00%
Dividend
Minimum [Member]
Class of Warrant or Right [Line Items]
Estimated future risk-free rate	2.35%	2.14%
Equivalent volatility	99.00%	85.00%
Equivalent risk-free rate	2.51%	1.30%
Maximum [Member]
Class of Warrant or Right [Line Items]
Estimated future risk-free rate	2.53%	2.45%
Equivalent volatility	104.00%	104.00%
Equivalent risk-free rate	2.55%	1.89%